1. Technical Field
The present disclosure relates to technologies used in a liquid crystal display device (LCD), a touch sensor (also referred to as a touch panel (TP)), a liquid crystal display device with a touch sensor (liquid crystal touch panel module), an electronic apparatus, and the like. Specifically, the present disclosure relates to technologies used in a liquid crystal display device with an in-cell capacitive touch sensor.
2. Description of the Related Art
As a liquid crystal display device with a touch sensor having a liquid crystal display function with a touch sensor function implemented, an in-cell touch panel configuration is employed especially for the purpose of reduction in thickness.
An example of the configuration of a related liquid crystal display device with an in-cell capacitive touch sensor (for example, Japanese Patent Application Laid-open Publication No. 2009-244958 (JP-A-2009-244958)) includes an array substrate, a color filter (CF) substrate, and a liquid crystal layer therebetween that are elements constituting the liquid crystal display panel. The configuration uses a common electrode (referred to as COM) on the CF substrate as a transmitting electrode (referred to as Tx) that is an element constituting the touch sensor function, and a detection electrode on the CF substrate as a receiving electrode (referred to as Rx). That is, the liquid crystal display function and the touch sensor function share the same electrode section and wiring.
In the above-described configuration example, a horizontal electric field mode or a vertical electric field mode may be applied as a driving system of the liquid crystal layer. The horizontal electric field mode is exemplified by fringe field switching (FFS) mode, in-plane switching (IPS) mode, etc. The vertical electric field mode is exemplified by twisted nematic (TN) mode, vertical alignment (VA) mode, electrically controlled birefringence (ECB) mode, etc.
In the case of the horizontal electric field mode, the wiring of the common electrode COM serving as the transmitting electrode Tx is only provided to a substrate (array substrate) on one side. On the other hand, in the case of the vertical electric field mode, the wiring of the common electrode COM serving as the transmitting electrode Tx exists on both top and bottom substrates, which are the array substrate and the CF substrate. That is, the configuration of the vertical electric field mode has one additional wiring layer of the common electrode compared with that of the horizontal electric field mode.
The liquid crystal display device with a touch sensor and the like typically have problems and requirements such as slimming down, space saving, simplification and reduction of manufacturing process and parts, that is, cost reduction by the simplification, and improvement in display quality and touch detection accuracy. Specifically, with regard to the simplification and reduction, employing an in-cell configuration in which an electrode and wiring are shared by different functions as described in the above configuration example enables reducing the number of layers to thereby achieve cost reduction.
An example of the related art of the above-described in-cell liquid crystal display device with a touch sensor is disclosed, for example, in PCT International Publication No. WO2007/070725. This patent document (“TOUCH SCREEN LIQUID CRYSTAL DISPLAY”) discloses “liquid-crystal display (LCD) touch screens that integrate the touch sensing elements with the display circuitry.”
With regard to the related liquid crystal display devices with an in-cell capacitive touch sensor, specifically with regard to configuration examples of sharing type in which the liquid crystal display function and the touch sensor function shared the same electrode section is shared (for example, as described in JP-A-2009-244958), a transparent electrode made of indium tin oxide (ITO) needs to be deposited, for example, on the color filter of the CF substrate to process a sensor pattern (pattern of the receiving electrode) for the touch sensor function in the manufacturing process of the liquid crystal display device with a touch sensor.
However, the manufacturing process of the liquid crystal display device with a touch sensor of sharing type requires a step for processing the sensor pattern and the like, so that the process is more complicated than that of the related liquid crystal display device with a touch sensor of non-sharing type and the like.
For the foregoing reasons, there is a need for a liquid crystal display device with an in-cell capacitive touch sensor (specifically, of sharing type) with a simplified configuration.